VFD Application
VFD Application
(OP)
Hi All,
I have recently installed a VFD unit on a 22Kw vent fan motor. The calculated yearly KWH without the VFD was calculated at 192852kwh. The data obtained from the VFD produced a yearly Kwh saving of 44195kwh; however according to the afinity law (at 80% the multiplier factor for the kwh was calculated to be 0.512). Therefore the obtained kwh at 80% for the year was calculated as 22*8766*.512=98470kwh; consequently abstaining a yearly Kwh saving of 94112Kwh. Can anyone give some suggestions as to the discrepancy between the calculated kwh savings and the VFD savings.
Thanks
I have recently installed a VFD unit on a 22Kw vent fan motor. The calculated yearly KWH without the VFD was calculated at 192852kwh. The data obtained from the VFD produced a yearly Kwh saving of 44195kwh; however according to the afinity law (at 80% the multiplier factor for the kwh was calculated to be 0.512). Therefore the obtained kwh at 80% for the year was calculated as 22*8766*.512=98470kwh; consequently abstaining a yearly Kwh saving of 94112Kwh. Can anyone give some suggestions as to the discrepancy between the calculated kwh savings and the VFD savings.
Thanks





RE: VFD Application
"Will work for salami"
RE: VFD Application
What does this mean? Exactly what data?
RE: VFD Application
Bill
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"Why not the best?"
Jimmy Carter
RE: VFD Application
The data received comprised of the total Kwh counter, the duration and the saved kwh from using the VFD. I will take a look at the losses of the VFD and also obtain data on running the VFD at 100% speed. Then explore the suggestion of Waross.
RE: VFD Application
Your simple calculations are wrong because you didn't include the motor efficiency.
Also, using the simple affinity law calculation shown on certain websites and by certain VFD salesmen can produce rather optimistic predictions.